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   51080
   SN 1993J is one of five recent supernova explosions (SNe) detected in
   X-rays. It is observationally unprecedented, in that it is the only SNe
   detected in the radio and in X-rays within a week of the explosion, and
   whose X-ray light curve and spectral evolution have been carefully
   measured for over one year. We detected X-ray intensity variations in
   last one year, which is faster than we expect from a shock heating
   models. Thus, continuous monitoring is urged. We also expect to detect
   emission from a pulsar, if it is as bright as Crab pulsar.
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